In plastic part production, parts are produced by injection molding or extrusion in large batch sizes and series using molds. The advantage of plastic injection molding rests in particular on the highly precise production of complex part geometries, wherein the versatility of operation of the injection molding process covers the requirements for an inexpensive and economical production of plastic parts in an optimal manner.
At the same time, demand for plastic parts in a unit number of one and small batch sizes such as pattern parts, for example, is increasing with the requirement of provision in a very short period as well as properties that are similar to those of injection molded parts. For the production of such parts there are production processes that are widely known by the term prototyping and rapid manufacturing. In most cases, the production of such parts is based on generation of the geometry from 3D data without tools, i.e. without molds. These geometries are produced in a wide variety of forms by appropriate means such as melting powder layers by application of heat, e.g. by means of lasers, generative systems such as printing processes in a different bonding form of the powder parts or also in the so-called melt extrusion process.
An extrusion method for producing objects during prototyping in processing metal based alloys is known from U.S. 2009/0314391 A1. An extrusion method requires low pressures for an continuous object generation, however, in order to keep away the high temperatures required for metallic alloys from the production system, a construction space surround is provided, in which a discharge unit, a processing unit as well as the object support are accommodated. The motor for moving the object support relative to the discharge unit is arranged outside the construction space.
A device, wherein a plasticizing unit known in injection molding technology is coupled to a pressurisable material storage device for generating a fluid phase of a material, is known from the patent EP 1 886 793 A1. To generate an object on an object support in a construction space, this material is discharged in the form of drops through a discharge opening, wherein because of the adhesion force of the material a high pressure and generally also high temperatures must be applied. The construction space can be temperature-controlled, as needed, for which purpose a temperature control unit is provided.
With such a solution, in which highly viscous fluid materials such as molten plastics are to be processed in extremely small quantities in discrete individual portions down to a few micrograms from a material storage device, which is under high pressure and possibly high temperature, temperature conditions quickly occur that influence the temperature control of the construction space.
It is known from DE 10 2009 030 099 A1 to provide in the device known from EP 1 886 793 A1 a construction space, in which the actuator for a solid joint for closing the outlet and also the object support with its movement mechanisms are accommodated, while the heat-generating processing unit remains outside the construction space.